在物理学的世界里，我们经常发现最简单的问题最难回答。
In the world of physics, we often find that the simplest questions are the hardest to answer.
Time is a slippery thing: lose hold of it once, and its string might sail out of your hands forever.
时间是个滑溜溜的东西：一旦失去控制，它的线索可能会永远从你手中溜走。
"In the middle of difficulty lies opportunity."
释义：如果人们能始终保持初相识时的那份真诚和友善，就能避免彼此之间的怨恨和纷争。
主动管理策略在扣除费用后不太可能产生优异的结果。